A frequency converter can be single or 3 phase and also change voltage thus functioning as a power converter from 50Hz to 60Hz, from 60Hz to 50Hz and from 50 / 60 Hz to 400 HZ. Several types of rotary frequency converter like LHFC series will monitor the input voltage and in the event of long term power failure so the logic will disconnect the load from the generator and shut down the unit. One major advantage of LHFC series is that thefrequency converter will remain stable through anything short of complete black out or disconnection, regardless of your utility supplied power condition.